GB1484944A - Apparatus for time control of the working operations of programmed appliances - Google Patents

Abstract

1484944 Time switches INDUSTRIAS COPRECI SCI 12 Aug 1974 [13 Aug 1973] 35355/74 Heading H1N [Also in Division F2] In a programmed timing apparatus, e.g. for use in a clothes-washing or dish-washing machine, having a pre-arranged sequence of of operations, a ratchet drive mechanism provides means for stopping the drive for programmable time intervals between consecutive operation stages, and comprises an indexable programme-carrying device 30, a reciprocating drive pawl member 49, and a separate ratchet wheel 41 having one or more recesses 10 deeper than other recesses 14, wherein the centre of rotation of the ratchet wheel 41 is caused to be moved relatively to the device 30 by cam means 32, 45 which thereby provide coupling between the indexed position of the programmecarrying device 30 and the position of the centre of rotation of wheel 41. Pinion 34 drives continuously a spiral cam 36 carried by wheel 35, Fig. 2, rotating it clockwise, and thereby drawing back member 49 against the tension of spring 37 until it reaches the position of Fig. 5. The position shown in Fig. 4 then follows, in which member 49 returning forward may impel the programme-carrying drum 30 through one increment of movement in direction 42, provided that pawl 39 has been able to engage one of the ratchet indentations 31. Member 49 is however provided with a second pawl 40 which can engage recesses 10 or 14 in ratchet wheel 41. When pawl 40 sinks into a deep recess 10, it may permit pawl 39 to engage an indentation 31, provided that the centre of wheel 41 is in a position which admits such engagement, as shown in Fig. 4. When pawl 40 engages a shallow recess 14, pawl 39 may be prevented from engagement, and the ratchet wheel 41 alone is then driven forward through one increment without advance of drum 30. Unit time intervals may thus be accumulated by progressive advance of ratchet wheel 41 retained against reverse motion by a detent pawl 45<SP>1</SP>. When subsequently cam follower 45 sinks into a cam recess 32, causing arm 43 to pivot about centre 44, the detent pawl 45<SP>1</SP> strikes a stop 48, thereby releasing wheel 41 to return to its starting orientation, under tension of spring 46.